Home » All Cars Sold In The U.S. Will Soon Have To Be Able To Automatically Avoid A Crash At 62MPH. Here’s Why That Could Be An Engineering Challenge

All Cars Sold In The U.S. Will Soon Have To Be Able To Automatically Avoid A Crash At 62MPH. Here’s Why That Could Be An Engineering Challenge

Aeb New Tests Ts

New regulations for automatic emergency braking have been bandied about for years, but the National Highway Traffic Safety Administration finally made them official this week. Come Sept. 1, 2029, almost all new cars sold in America must have automatic emergency braking that can come to a complete stop and avoid a stopped vehicle ahead from 62 mph. It’s an aggressive target, and while well-intentioned, it’s a challenge that comes with a few strange exemptions and potential pitfalls.

See, these rules won’t quite apply to all vehicles. Some vehicles will see delayed introductions, some vehicles are exempt, and some vehicles will have varying ways of disabling automatic emergency braking. First, low-volume manufacturers get an extra year, until Sept. 1, 2030, to implement this new tech.

Vidframe Min Top
Vidframe Min Bottom

Next, these regulations don’t apply to any vehicle with a gross vehicle weight rating of more than 10,000 pounds. GMC Hummer EVs, certain heavy-duty pickup trucks, semi trucks, and basically anything with “Final Destination” levels of mass is exempt from these regulations. Finally, there both will and won’t be ways to defeat these future automatic emergency braking systems. I’ll let NHTSA explain.

NHTSA includes in this final rule an explicit prohibition against manufacturers installing a control designed for the sole purpose of deactivating the AEB system but allows for controls that have the ancillary effect of deactivating the AEB system (such as deactivating AEB if the driver has activated “tow mode” and the manufacturer has determined that AEB cannot perform safely while towing).

So, if you’re expecting a hard button to turn off automatic emergency braking, good luck, but such a function may be bundled into track mode on performance cars, towing mode on trucks, certain off-road modes on SUVs, low-range 4X4, or even disabling stability control.

At speeds of up to 62 mph, these next-generation automatic emergency braking systems must avoid a collision with a vehicle stopped on the roadway ahead. Sounds great, but it’s worth keeping in mind that braking distance is proportional to the square of the initial speed. Essentially, a car will need four times the distance to stop from 60 mph than it would from 30 mph, and given what we’ve seen from current automatic emergency braking systems, that will certainly present a challenge.


Recently, the Insurance Institute for Highway Safety revised its automatic emergency braking testing to include a motorcycle and a semi-trailer, and to up speeds from 18 and 25 mph to 31, 37, and 43 mph. Four of the ten compact crossovers tested under the revised procedures scored the institute’s lowest rating of “Poor,” and the Chevrolet Equinox provides a textbook example. As per an IIHS media release: “With the passenger car target, it slowed modestly in the 31 mph tests, and with the motorcycle target it barely reduced speed at all.”

Note that “slowed modestly” doesn’t equal stopping. A number of systems on the market today fail testing at half the speed the new regulations, and these new regulations give automakers just over four years to get their systems up to speed. Unsurprisingly, automakers are unsure whether this is possible, but carmakers aren’t the only ones.

Bosch Aeb

Take automotive supplier Bosch, which has an interest in supplying automakers with better and more expensive sensor suites because that’s how money is made. In theory, this company should be all for stricter automatic emergency braking requirements, but during comment period, the firm raised some concerns. As per NHTSA:


Bosch stated that its testing shows that when the speed reaches approximately 75 km/h, there are reproducibility challenges with multi-sensor fusion of the object in time to initiate AEB and avoid the obstruction, and considerations should be made on how these requirements align with current functional safety requirements.

Translation? Higher speeds affect the reliability of obstacle detection. Now, NHTSA has gone with a no-contact rule in testing under these new regulations, and the way to fudge for margin of error on that is to increase the envelope of what constitutes an automatic emergency braking event. However, phantom braking can be just as dangerous as not coming to a stop due to creating a speed delta, and NHTSA’s upcoming tests false positive braking events aren’t entirely confidence-inspiring.

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One test involved driving between two parked cars, and that should be easy enough. Another involves driving over a steel trench plate, which is fairly standard by now. Note the absence of glare testing for camera-based systems; testing that incorporates lane shifting like in a construction zone; or testing for excessive sensitivity while following a vehicle. Oh, and did I mention that NHTSA’s phantom braking tests still allow some amount of braking of less than 0.25g higher peak deceleration than manual braking would entail? Again, not ideal.

Screenshot 2024 04 25 At 4.46.10 pm automatic emergency braking

Legislating stronger automatic emergency braking comes with great intentions, but it’s yet to be seen whether these beefed-up systems can function reliably and meet regulations. Given how long product stays on sale these days, 2029 may be less than one model cycle away for some vehicles, so automakers are likely already trying to crack this challenge. Whatever happens, it’s going to be interesting.


(Photo credits: Bosch, IIHS)

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2 months ago

I experienced this fun a year or so ago in a rented Explorer. The emergency stop system did an excellent job of scrubbing off speed even starting from 70mph. Which is not a good thing when there’s open road in front of you and another vehicle behind you. Luckily they were paying enough attention not to hit me and just swerved around honking at the idiot who’d come to a near stop on the interstate for no good reason.

Shooting Brake
Shooting Brake
2 months ago

Lot of concerns about how this is implemented, a lot of the current systems are so bad they are best turned off…

2 months ago

The problem NHTSA is trying to “fix” is that people don’t pay attention behind the wheel and smack into things. The ingenious solution they came up with was to mandate the auto industry to make their products MORE complex, MORE expensive, and MORE costly to repair just to end up with a system that best case probably won’t work properly in boundary usage conditions. Somebody needs to tell NHTSA that the car tech isn’t what’s deficient anymore. It’s the meat bag in the driver’s seat.

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